This invention relates to an assembly apparatus for retaining rings.
An assembly apparatus of this type, as disclosed, for example, in DE-OS No. 3,413,478, is employed to mechanically insert slit radially resilient retaining rings in the respective annular grooves on a shaft or the like, or in a housing. The retaining ring has assembly holes that receive corresponding bolt projections of a clamping or tensioning arrangement. The retaining ring thereby extends radially and is positively held in at least one axial direction, and is oriented in a position suitable for assembly.
The clamping jaws employed in this arrangement are pivoted a predetermined extent with respect to one another by the movement of a prism, and the retaining ring is thereby radially tensioned. In this tensioned condition, the retaining ring is guided into a bore having a corresponding annular groove. Upon loosening the clamping jaws, the retaining ring snaps into the annular groove. The assembly apparatus is then moved back to its initial position. All movements are automatically controlled for the reception of a new retaining ring.
The above described assembly apparatus can only operate without failure in automatic operations, over an extended time, if the retaining rings are all identical. When using retaining rings from various sources, or when the retaining rings have small differences in cross section of the materials that are used, even insignificant deviations can arise in the radial tension force. In mass production, the resultant variations in radial seating, axial force carrying capacity, etc. of the retaining ring, are not acceptable, especially in the assembly of reliable, quality high grade products. Moreover it must also be expected that individual faulty retaining rings may be inadvertently assembled, since the unsatisfactory seating of retaining rings, in the known assembly apparatus, as a result of improper tension forces during the tensioning about the constant radial path, may not be noticeable.
Furthermore it can not be assured, in the above described apparatus, whether or not the retaining ring guided thereby is actually snapped into the annular groove